Realplayer keeps reassigning default program for media files?

I downloaded and installed RealPlayer a few days ago. Now all of my media are set to up with RealPlayer instead of WMP. I tried to manually change it by using "Open With" and clicking "Always use this program to open this type of file" but it always comes back. Anyone have any insight into this. Oh and I'm running Win2k right now but I'm sure it's a RealPlayer issue and not anything to do with windows.